The present disclosure relates generally to sensors for measuring the speed of an aircraft relative to its surrounding air mass (hereinafter “air speed”).
Aircraft require ownship air speed measurements in flight for aircraft handling, aerodynamics and potential stalling. This is usually done with a Pitot tube, which consists of a tube pointing directly into the air flow. Using internal fluid which is compressed under air pressure, the fluid pressure can be measured and used to compute the stagnation pressure of the air. To compute the air velocity, a comparison is made against the static pressure measured from static ports feeding a barometer. Then using Bernoulli's equation, the dynamic pressure (hence the air speed) can be computed.
Modern Pitot tubes are heated but still have problems with icing and blockage that make their usage problematic under certain conditions. More specifically, the Pitot tube can be blocked by external matter while the plane is grounded, the Pitot tube can still ice up even with heating, and the Pitot tube increases drag relative to a solution that is able to conform more closely to the exterior shape of the aircraft.
There is a need for an alternative methodology for measuring air speed that is not affected by icing or other blockage issues and that decreases drag.